We characterize the mechanical properties of a selected number of alloys with respect to anisotropy, build thickness and surface roughness. We develop constitutive and life models for use in design and topology optimization. We extend topology optimization to include AM specific properties with respect to anisotropy, residual stresses and grid-like structures.
The combination of additive manufacturing (AM) and topology optimization is a powerful tool in order to design and manufacture components with complex geometries and optimized performance. In the thin walled structures that are typically generate, good knowledge and control of the mechanical properties will be important.
However, even if the chemical composition is the same, the properties of material produced by AM can differ significantly compared to that of conventionally produced material. This is due to the inherent nature of the AM processes which gives a unique microstructure within the material. Also, the microstructures and the properties may vary with orientation, and location within the component. In addition, during the build process high residual stresses will be generated in the component being made. The unique behaviour of the AM materials need to be further characterized and included in the topology optimization framework.
Three initiatives
In each research area there are specific ongoing initiatives. In this area, there are three:
- Characterization of inhomogeneous and anisotropic material properties
The focus is to investigate the effect of anisotropy on tensile properties, fatigue properties, toughness and fracture. We will also study the influence of thickness and surface roughness on mechanical properties and do work on validation of optimized and grid-like structures.
- Novel TO methods including AM specific properties
Topology optimization (TO) methods will be extended to include; anisotropic material behaviour (optimal build direction), fatigue constraints and residual stresses. We will develop TO methods for design of grid-like structures; Repetitive cell structure, Free optimal fine scale structure. Work will also be done on TO methods taking uncertainty into account (Robust design).
- Role of powder properties and EBM parameters on segregation, residual stress and anisotropy in Ni-base superalloy builds
The focus is to estimate the cooling rate within a layer and along build direction during a typical EBM hatch theme and study the effect of EBM process parameters (beam speed, scan strategy, focus offset) on intrinsic parameters (cooling rate, solidification mode) and microstructure
Research Area Leaders
Researchers
Prof. Anders Klarbring, Linköping University
Assoc. Prof. Carl-Johan Thore, Linköping University
Assoc. Prof. Bo Torstenfelt, Linköping University
Dr Masoud Rashidi, post-doctoral researcher, Chalmers University of Technology
Prof. Ru Peng, Linköping University
Prof. Robert Pederson, University West
Assoc. Prof. Joel Andersson, University West
Shyam Suresh, PhD-student, Linköping University
Cheng-Han Yu, PhD-student, Linköping University
Magnus Kahlin, Industrial PhD student from Saab AB/Aeronautics
Olutayo Adegoke, PhD-student, University West
Cosmina Ioana Luchian, MSc student, Chalmers University of Technology
Partners involved
Linköping University, University West, Atlas Copco, Arcam, GKN Aerospace, Höganäs, SAAB, Sandvik, Siemens IT AB, Volvo Car Group, Volvo GTO.